1. Field of the Invention
The invention relates to a corduroy cutting machine having a shaft on which a plurality of circular knives are mounted adjacent one another, the knives being insertable into longitudinal slots formed in needles which are respectively pushed into floating wefts to be cut open in the direction opposite the travel of the fabric web, a contact table disposed below the needle points for activating a switch for stopping the machine when touched by a needle, and a rear table disposed before the needle points in the fabric web travel direction, at a distance from the contact table, the rear table being held during the cutting operation in a working plane extending through the needles and the contact table, the fabric web being drawn from below into the working plane and over the contact table to a cutting edge which is opposite the circular knives, and the rear table and the contact table being lowered at random from the working plane.
2. Description of the Prior Art
Corduroy machines are known, for example, from German Patent DE-PS 27 40 402. These machines serve for producing filling or weft pile fabric, particularly ribbed velvet. In the case of filling pile fabric, the pile is obtained by means of a special weft, the right-side floats of which are cut open in a corduroy cutting machine. The cutting occurs during an operation wherein the fabric, subjected to tension in the warp direction, is drawn over a cutting edge, which acts together with a knife shaft. In this way, the floating wefts form tubes, and each tube runs onto one of the needles. Each needle has a longitudinal slot, into which one of the circular knives mounted on the knife shaft is partially inserted. Through adjustment of the knife shaft, swiveling vertically to the longitudinal axis thereof, the gap between the periphery of the circular knives and the cutting edge of the machine can be adjusted so that the floating wefts of the web travelling through are cut, but the ground web or backing is undamaged.
For normal operation of the machine, it is preferable for the needles to be intermittently pushed for guidance, so that the needle points exit neither outward through the ground web or backing nor upward from the tube. In the case of such a needle withdrawal, special contact rails are disposed above and below the needles so that one needle withdrawal results in a respective signal for an immediate stop of the machine. During the operation of a corduroy cutting machine, in many cases sewn-together pieces having a length of 100 to 120 meters are cut in turn. By using fabric speeds of only 10 meters per minute, the net cutting time per piece is also approximately 10 to 12 minutes. Following a transferring of needles, for example, five needles per centimeter fabric width are required from the finished cut piece to the next piece to pass over the seam in question. This needle transfer lasts through the time for withdrawing the needles from the finished piece and the insertion of the needles into the next piece.
The time for withdrawal, which in previous machines was approximately one-third of the total transfer time, can be substantially reduced according to German Published, Non-Prosecuted Application DE-OS 30 33 792, corresponding to U.S. Application Ser. No. 600,604, now U.S. Pat. No. 4,532,683, granted Aug. 6, 1985, when the stretched fabric web, drawn over the contact table to the cutting edge, is randomly pulled downward together with the contact table, so that all of the needles exit upward and thereby cut the needles free altogether at the fabric speed. A withdrawal of the needle is also no longer required, while the needles are automatically cut out from their respective fabric tube by the circular knife, because of the fabric web course, which is angular or bent downward from the working floor, respectively.
However, the corduroy cutting machine according to German Published, Non-Prosecuted Application DE-OS 30 33 792 and the method thereof for cutting the needles free before a seam, have proved that a certain danger exists for so-called fine cords, for which only very thin needles can be used because of the closeness of the side by side tubes. The danger is that of bending of the needle points and therefore of the destruction of the needles generally, when the rear table and the contact table are lowered and the needles do not have enough inherent stability to resist the tension of the inclined fabric web.